3. RunKeeper

The prospect of Nike+ but better and for free might sound unlikely, but that's what RunKeeper provides. Previously split into 'pro' and 'free' versions, the developer now generously includes all the features in one free app.

That means you can spend no money, yet use your iPhone's GPS capabilities to track your jogging and cycling routes, and examine mapping and details of your pace and calories burned. Activities can be shared online, and treadmill runs and other exercise details can be entered manually.